There was a case not long ago where a man was getting attacked by an angry Bald Eagle here in Florida... The D.A. said that the law, as he interpreted it, didn't protect any species from someone trying to protect themselves.
I guess the only catch with this case is the hunter originally shot the grizzly thinking it was a black bear; the self defence only came later as they tried to track down the bear he shot.
It will be interesting to see if he ends up getting charged under the Endangered Species Act based on the fact that he shot a protected species due to his misidentification of the animal.